Charged air mass measurement for air data computation

Abstract

Systems and methods for enabling charged (ionized) air mass measurement for reliable air data computation onboard an aircraft. Ionic charge sensing may be used to derive air data having improved reliability. The systems and methods for ionic charge sensing employ an emitter electrode and two or more collector electrodes, which electrodes are disposed in proximity to the exterior skin of the aircraft and exposed to ambient air. The emitter electrode is positioned forward of the collector electrodes. The system further includes a solid-state ionic air data module that converts currents from the collector electrodes into air data parameter values. More specifically, the ionic air data module is configured to sense currents induced in the collector electrodes in response to corona discharge produced by the high-voltage emitter electrode.

The invention claimed is: 
     
       1. An aircraft comprising:
 an exterior skin having an aerodynamic surface and first, second, and third cavities which are open to an ambient atmosphere, the first cavity being disposed at a position which is forward of respective positions of the second and third cavities; 
 a power supply; 
 an emitter electrode comprising a first electrically conductive wire which is connected to the power supply and has a tip which is disposed in or protrudes from the first cavity; 
 a first collector electrode comprising a second electrically conductive wire which is connected to ground and is disposed in the second cavity; 
 a second collector electrode comprising a third electrically conductive wire which is connected to ground and is disposed in the third cavity; 
 a first current sensor having an input connected to the first collector electrode and having an output; 
 a second current sensor having an input connected to the second collector electrode and having an output; and 
 a microcontroller connected to receive first and second output signals from the first and second current sensors respectively and configured to compute an ionic air data parameter value based at least in part on a relationship between respective magnitudes of the first and second currents, 
 wherein the second and third electrically conductive wires are straight, mutually coaxial, separated by a gap, and arranged so that respective currents are induced in the first collector electrodes by ionic wind flowing in a boundary layer adjacent the aerodynamic surface while power is being supplied to the emitter electrode during flight of the aircraft. 
 
     
     
       2. The aircraft as recited in  claim 1 , wherein the microcontroller comprises a non-transitory tangible computer-readable storage medium storing a calibration table which correlates relationships between respective magnitudes of first and second currents and air data parameter values recorded during testing. 
     
     
       3. The aircraft as recited in  claim 1 , wherein the relationship is a difference between the respective magnitudes of the first and second currents. 
     
     
       4. The aircraft as recited in  claim 3 , further comprising an air data and inertial reference unit (ADIRU) which is connected to receive the ionic air data parameter value from the microcontroller. 
     
     
       5. The aircraft as recited in  claim 4 , wherein the ADIRU is configured to compute an estimated airspeed which is a function of a velocity of the aircraft and the ionic air data parameter value received from the microcontroller. 
     
     
       6. The aircraft as recited in  claim 4 , wherein the ADIRU is configured to compute an estimated pressure which is a function of static pressure outside the aircraft and the ionic air data parameter value received from the microcontroller. 
     
     
       7. The aircraft as recited in  claim 4 , wherein the ADIRU is configured to compute an estimated total air temperature which is a function of static air temperature outside the aircraft and the ionic air data parameter value received from the microcontroller. 
     
     
       8. The aircraft as recited in  claim 1 , wherein the relationship is a ratio of the respective magnitudes of the first and second currents. 
     
     
       9. The aircraft as recited in  claim 8 , wherein the ionic air data parameter is an estimated angle of attack and the estimated angle of attack is a function of the ratio of the respective magnitudes of the first and second currents. 
     
     
       10. The aircraft as recited in  claim 1 , wherein the tip of the first electrically conductive wire is situated such that free electrons propagate within the boundary layer at the aerodynamic surface during flight of the aircraft while the power supply is providing power to the emitter electrode. 
     
     
       11. The aircraft as recited in  claim 1 , wherein the first and second collector electrodes have a same size and are arranged symmetrically with respect to the emitter electrode, and an axis of the emitter electrode lies in a plane of symmetry that passes through a midpoint of the gap and is perpendicular to an axis of the first and second collector electrodes. 
     
     
       12. The aircraft as recited in  claim 1 , wherein the first cavity is circular and the second and third cavities are linear. 
     
     
       13. An aircraft comprising:
 an exterior skin having an aerodynamic surface and first, second, and third cavities which are open to an ambient atmosphere, the first cavity being circular and disposed at a position which is forward of respective positions of the second and third cavities which are not circular; 
 a power supply; 
 an emitter electrode comprising a first electrically conductive wire which is connected to the power supply and has a tip which is disposed in or protrudes from the first cavity; 
 a first collector electrode comprising a second electrically conductive wire which is connected to ground and is disposed in the second cavity; 
 a second collector electrode comprising a third electrically conductive wire which is connected to ground and is disposed in the third cavity; 
 a first current sensor having an input connected to the first collector electrode and having an output; 
 a second current sensor having an input connected to the second collector electrode and having an output; and 
 a microcontroller connected to receive first and second output signals from the first and second current sensors respectively and configured to compute an ionic air data parameter value based at least in part on a relationship between respective magnitudes of the first and second currents, 
 wherein the second and third electrically conductive wires have respective tips which are separated by a gap, and are configured and arranged so that respective currents are induced in the first and second collector electrodes by ionic wind flowing in a boundary layer adjacent the aerodynamic surface while power is being supplied to the emitter electrode during flight of the aircraft. 
 
     
     
       14. The aircraft as recited in  claim 13 , wherein the tip of the first electrically conductive wire is situated such that free electrons propagate within the boundary layer at the aerodynamic surface during flight of the aircraft while the power supply is providing power to the emitter electrode. 
     
     
       15. The aircraft as recited in  claim 13 , wherein the first and second collector electrodes have a same size and a same shape and are arranged symmetrically with respect to the emitter electrode. 
     
     
       16. The aircraft as recited in  claim 13 , wherein the second and third electrically conductive wires are straight and mutually coaxial. 
     
     
       17. A charged air mass measurement device comprising:
 a power supply; 
 an emitter electrode comprising a first electrically conductive wire having a tip which is electrically connected to the power supply during the supplying of power; 
 a first collector electrode comprising a second electrically conductive wire which is connected to ground; 
 a second collector electrode comprising a third electrically conductive wire which is connected to ground; 
 a first current sensor having an input connected to the first collector electrode and having an output; 
 a second current sensor having an input connected to the second collector electrode and having an output; and 
 a microcontroller connected to receive first and second output signals from the first and second current sensors respectively and configured to compute an ionic air data parameter value based at least in part on a relationship between respective magnitudes of the first and second currents, 
 wherein the second and third electrically conductive wires are straight and mutually coaxial, have respective tips which are separated by a gap, have a same size, and are arranged symmetrically with respect to the emitter electrode. 
 
     
     
       18. The charged air mass measurement device as recited in  claim 17 , wherein the tip of the emitter electrode lies in a plane of symmetry that passes through a midpoint of the gap and is perpendicular to an axis of the first and second collector electrodes. 
     
     
       19. The charged air mass measurement device as recited in  claim 17 , wherein the microcontroller comprises a non-transitory tangible computer-readable storage medium storing a calibration table which correlates relationships between respective magnitudes of first and second currents and air data parameter values recorded during testing. 
     
     
       20. The aircraft as recited in  claim 17 , further comprising an air data and inertial reference unit (ADIRU) which is connected to receive the ionic air data parameter value from the microcontroller.